In recent years, there has been an increasing use of compact, pocket-size electronic personal organizers that store personal scheduling information such as appointments, tasks, phone numbers, flight schedules, alarms, birthdays, and anniversaries. Some of the more common electronic organizers are akin to hand-held calculators. They have a full input keyboard with both numeric keys and alphabet keys, as well as special function keys. The organizers also have a liquid crystal display (LCD) which often displays full sentences and rudimentary graphics.
Pocket-size personal organizers prove most useful to busy individuals who are frequently traveling or always on the move from one meeting to the next appointment. Unfortunately, due to their hectic schedules, these individuals are the people most likely to forget their personal organizers during the frantic rush to gather documents, files, laptops, cellular phones, and travel tickets before heading off to the airport or train depot. It would be desirable to reduce the number of electronic devices that these individuals need to remember for each outing.
Electronic watches have evolved to the point that they can function as personal organizers. Like the pocket-size devices described above, such watches can be programmed with certain key appointments, tasks, phone numbers, flight schedules, alarms, birthdays, and anniversaries. Since watches are part of everyday fashion attire, they are more convenient to carry and less likely to be forgotten by busy people. However, it is much more difficult to enter data into a watch than it is to enter the same data into a pocket-size personal organizer. This difficulty is due in large part to the limited number of input buttons and display characters available on reasonably-sized watches. Most watches are limited to having only three or four input buttons. A wearer programs a watch by depressing one or more buttons several times to cycle through various menu options. Once an option is selected, the user depresses another button or buttons to input the desired information. These input techniques are inconvenient and difficult to remember. Such techniques are particularly inconvenient when a wearer wishes to enter an entire month's schedule. Although watches have been made with larger numbers of input keys, such watches are usually much too large for comfort, and tend to be particularly unattractive.
Apart from personal organizers, it is common for many people to maintain appointment calendars and task lists on their personal computers. One example time management software is Microsoft's.RTM. Schedule+.TM. for Windows.TM. which maintains daily appointment schedules, to-do lists, personal notes, and calendar planning. This information is often a duplicate of that maintained on the portable personal organizer.
Timex Corporation of Middlebury, Conn., has recently introduced the Timex.RTM. Data-Link.TM. watch. This watch utilizes new technology for transferring information from a personal computer to a watch. The face of the watch has an optical sensor which is connected to a digital serial receiver, better known as a UART (universal asynchronous receiver/transmitter). The watch expects to receive a serial bit transmission in the form of light pulses at a fixed bit rate. A pulse represents a binary `0` bit, and the absence of a pulse represents a binary `1` bit.
The CRT (cathode ray tube) or other scanned-pixel display of a personal computer is used to provide light pulses to the watch. Although it appears to a human viewer that all pixels of a CRT are illuminated simultaneously, the pixels are actually illuminated individually, one at a time, by an electron beam which sequentially scans each row of pixels beginning with the top row and ending with the bottom row. It is this characteristic of a CRT and of other scanned display devices which is utilized to transmit serial data to the Data-Link.TM. watch. To transfer data to the watch, the watch is held near and facing the CRT. The computer is programmed to display a sequence of display frames in which spaced horizontal pixel lines represent individual bits of data to be transferred. Lines are illuminated or not illuminated, depending on whether they represent binary `0` bits or binary `1` bits. Each line appears as a continuous pulse of a finite duration to the receiving watch. The watch recognizes an illuminated line as a binary `0` bit. It recognizes a non-illuminated line as a binary `1` bit. Generally, ten bits are transmitted in a single CRT display frame: eight data bits, a start bit, and a stop bit. As used herein, the term "display frame" means a single screen-size image made up of a matrix of pixels. A display frame is generally created by sequentially illuminating or refreshing the pixels of the display device.
One of the drawbacks in remotely programming small-size personal organizers is that there is no convenient way to partially download data. Instead, entire data sets must be fully downloaded during each programming session. If a data entry error is made or the user wishes to make a change, the user must fix the error or make the change at the computer end and then transmit the entire data set back to the watch to essentially reprogram it, even though the data entry error or change might be minor.
The inability to partially download data is primarily due to the fact that the watch can only receive information from the computer CRT, but cannot send any information back. That is, the optical communication channel is one-way from the CRT to the watch. This one-way communication makes partial downloading extremely difficult.
Limited memory capacity of compact personal organizers is another significant reason that inhibits the ability to intelligently move data and accept partial new data on the watch. The Timex.RTM. Data-Link.TM. watch has approximately 1 Kbyte of DRAM (Dynamic Random Access Memory) for storing data and approximately 23 Kbytes of ROM (Read Only Memory) for storing programs and functions. There is simply no space for maintaining local memory management functions. Even when memory capacity improves in personal organizers, as it is expected to do, designers will most likely strive to fully utilize all memory capacity for storing data and program instructions as opposed to reserving significant space for memory management.
Furthermore, processing capabilities and power of portable personal devices are limited. Providing local memory management functions might simply be too overwhelming.
Accordingly, it is an object of this invention to provide a memory management technique that enables a user to partially download data from the computer to the electronic personal organizer.